JPH1144963A - Electrophotographic toner - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a toner having stable electrostatic charge characteristics independent of en environmental change over a long period of time. SOLUTION: The toner consists essentially of a bonding resin, a colorant and a releasing agent incompatible with the bonding resin. The dispersion diameter of the releasing agent is <0.2 μm and the toner has inorg. fine particles stuck to the surfaces of particles. The quantity of electric charges of the toner is in the range of -10 to -5O μc/g or in the range of 10-50 μc/g and the difference between the quantity of electric charges of the particles before the addition of the inorg. fine particles and that of the toner after the addition of the inorg. fine particles does not exceed 50% of the quantity of electric charges of the toner.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electrophotographic toner having stable charging characteristics for a long period without being affected by environmental changes.

[0002]

2. Description of the Related Art Electrophotography generally utilizes a photoconductive substance, forms an electric latent image on a photoreceptor by various means, and then develops the latent image with toner. After transferring the toner image to a transfer material such as paper, the toner image is fixed by heating, pressure, heat pressure or solvent vapor to obtain a copy.

As described above, the toner is first transferred from the developing device to the photosensitive member and then from the photosensitive member to the transfer member.
The toner must maintain fluidity between the toners and releasability from an object to be contacted. Further, it is necessary to prevent the aggregation of the toner particles in the developing device. Conventionally, in order to solve such a problem, a method has been used in which inorganic fine particles having a smaller particle diameter than toner particles are mixed as an external additive.
Some of the inorganic fine particles have a function of charge control in addition to imparting fluidity.

Incidentally, silica fine particles and titania fine particles are used in combination as disclosed in JP-A-60-136755 and JP-A-2-43564, or two types of inorganic fine particles having different polarities are used in combination as disclosed in JP-A-5-74818. For example, a toner that offsets an increase and a decrease in charging characteristics has been disclosed. Japanese Patent Application Laid-Open No. 6-43694 discloses a toner in which the charge amount after external addition of inorganic fine particles is higher than the charge amount before external addition. Conversely, in Japanese Patent Application Laid-Open No. 8-328291, the charge amount after inorganic particle addition is externally added. A toner having a charge amount lower than the previous charge amount has been proposed. However, in these toners, a phenomenon occurs in which the external additive is buried in the toner over time, and the charging characteristics change. This phenomenon becomes more conspicuous in the case of toners to which a release agent has been added, in accordance with the recent trend toward oillessness. further,
In the case of a full-color toner, a resin having a low softening point is necessary in consideration of color development and color mixing. For such resins,
Since the release agent needs to be sufficiently exuded and the release agent needs to be present with a dispersed diameter, it is considered that the external additive is more likely to be buried, and the change in the charging characteristics is large. It will be something. In some cases, the external additive increases the change in the amount of charge due to the environment.

[0005]

SUMMARY OF THE INVENTION An object of the present invention is to provide a toner which has stable charging characteristics over a long period of time and has excellent characteristics which are not affected by environmental changes.

[0006]

According to the present invention, (1)
At least the binder resin, the colorant, and the binder resin are made of an incompatible release agent, and the release agent dispersion diameter is smaller than 0.2 μm,
A toner having inorganic fine particles adhered to the particle surface, wherein the charge amount of the toner is in a range of −10 μc / g to −50 μc / g, or in a range of 10 μc / g to 50 μc / g;
The difference between the charge amount of the particles before the addition of the inorganic fine particles and the charge amount of the toner after the addition of the inorganic fine particles is 50% of the charge amount of the toner.
(2) a toner for electrophotography, which does not exceed
At least the binder resin, the colorant, and the binder resin are made of an incompatible release agent, and are toners having inorganic fine particles adhered to the particle surface. The binder tree present in the toner has a THF-insoluble component. The toner has a dispersion diameter of the release agent of 0.2 to 1 μm and a charge amount of the toner in the range of −10 μc / g to −50 μc / g, or in the range of 10 μc / g to 50 μc / g. A full-color toner for electrophotography, wherein the difference between the charge amount of the particles and the charge amount of the toner after the attachment of the inorganic fine particles does not exceed 30% with respect to the charge amount of the toner.
(3) The toner for electrophotography according to the above (1) or (2), wherein the external additive is a combination of two or more kinds, and (4) the charge amount of the release agent before the addition of the inorganic fine particles. (5) The toner for electrophotography according to the above (2) or (3), wherein the difference in charge amount after addition of the inorganic fine particles does not exceed 80% of the charge amount after addition of the inorganic fine particles. )
(1) to (1) to (4), characterized by containing a charge control agent.
(3) The electrophotographic toner according to any one of (2) to (5), wherein (6) the loose apparent specific gravity of the particles before the attachment of the inorganic fine particles is 0.35 or more. (7) The toner for electrophotography according to the above (7), wherein the penetration of the release agent is 15 or less.
The electrophotographic toner according to any one of (6) is provided.

Hereinafter, the present invention will be described in more detail. The toner for electrophotography (hereinafter also referred to as toner) of the present invention is characterized in that a difference in charge amount between particles before addition of inorganic fine particles and toner after addition is set to be small. That is, the present invention is devised so that the external additive (inorganic fine particles) does not greatly increase or decrease the charge amount. Generally, the external additive is buried in the surface of the particle with the lapse of time although there is some difference. However, when a release agent that is incompatible with the binder resin is used, the release agent exists on the particle surface. Since the release agent is softer than the binder resin, the external additive is more easily buried in the particles containing the release agent than in the particles not containing the release agent. This is especially true if the release agent has a large dispersion diameter. According to the present invention, the dispersion diameter of the release agent is set to 0.1.
Since the thickness is smaller than 2 μm, the burying phenomenon of the external additive can be reduced. If the difference between the charge amounts before and after the addition of the external additive is large, the charge amount increases or decreases together with the buried amount of the external additive. Therefore, in the present invention,
It is necessary that the difference between the charge amounts before and after the addition of the inorganic fine particles does not exceed 50% of the charge amount after the addition.

In many cases, the external additive is provided with both functions of improving the fluidity and controlling the charge. One additive having both functions and having no change in the charge amount with the base particles is used. It is difficult to find from the kinds of external additives. Therefore, it is preferable to appropriately combine two or more kinds of external additives to improve fluidity and control charging.

The charge amount of the toner and the particles before the addition of the external additive in the present invention is based on the following measuring method. The charge amount of the toner is 2 to 50 g of the carrier.
A toner in a range of 7% is put in a plastic container, mixed by stirring with a ball mill stand for 20 minutes, and measured by a blow-off method. As for the particles before the addition of the external additive, particles having the same ratio as in the case of the toner with respect to 50 g of the carrier are similarly stirred and mixed, and measured by a blow-off method.

In the present invention, the charge amount of the toner is -1.
0 μc / g to −50 μc / g, or 10 μc / g
g to 50 μc / g. If the charge amount of the toner is a value having an absolute value smaller than -10 or 10 μc / g, toner scattering or background stain on an image portion occurs. If the absolute value is larger than -50 or 50 [mu] c / g, the adhesion between the toner and the carrier surface or the sleeve is strong, so that spent, filming, and blade sticking are likely to occur.

By the way, in a full-color toner,
It is necessary that the superimposed toners of the respective colors are sufficiently melted. For this purpose, the binder resin in the toner preferably has no THF-insoluble component. Further, since the cohesive force of the binder resin itself is weakened, it is desirable that the dispersion diameter of the release agent is set to 0.2 μm or more. If the dispersion diameter of the release agent is smaller than 0.2 μm, the release agent at the time of fixing may not sufficiently exude, resulting in a toner having a narrow fixing temperature range. However, if the dispersion diameter of the release agent is too large, the fluidity of the particles may be deteriorated. Therefore, in the full color toner of the present invention, the dispersion diameter of the release agent is preferably set to 0.2 to 1 μm.

In the present invention, the presence or absence of a THF-insoluble component is determined as follows. About 1 g of the toner is weighed, 50 g of THF is added thereto, and the mixture is allowed to stand at 20 degrees for 24 hours.
This is first separated by centrifugation, according to JIS (P3801)
Filter at room temperature using 5C quantitative filter paper. Subsequently, the filter paper residue is an insoluble matter, and is represented by the ratio (wt%) between the used toner and the filter paper residue. Since solids such as pigments are present in this residue, they are separately determined by thermal analysis or the like.

The compatibility / incompatibility of the release agent and the binder resin and the dispersion state of the release agent can be confirmed by a transmission electron microscope. The definition of compatibility / incompatibility in the present invention is as follows. This is based on a 100,000-times enlarged photograph using a transmission electron microscope.

In the case of a full-color toner which requires a large dispersion diameter of the release agent and a soft binder resin, the external additive is more easily buried. Therefore, it is preferable that the difference in charge amount between before and after the addition of the external additive is set so as not to exceed 30% of the charge amount of the toner.

Further, the full color toner is more likely to be affected by the charging characteristics of the release agent since the surface presence of the release agent is higher than that of the black toner. Therefore, it is preferable that the difference in the amount of charge of the release agent depending on the presence or absence of the external additive is small. Therefore, in the present invention, it is preferable that the difference in the charge amount of the release agent before and after the addition of the external additive does not exceed 80% with respect to the charge amount of the release agent after the addition. If it exceeds 80%, it may be difficult to reduce the difference in charge amount between before and after the addition of the external additive to the toner.

The charge amount of the release agent referred to in the present invention is determined by crushing the release agent to a toner size, and adding 2 to 7% by weight (the same concentration as the toner) of the release agent to 50 g of the carrier. Means a value measured by stirring and mixing in the same manner as in the above case. The charge amount of the release agent to which the external additive is added is measured by adding the same amount of the external additive to the toner as to the release agent.

The toner of the present invention can be made into particles which are less susceptible to external additives by including a charge control agent. In addition, the fact that the charge amount does not change before and after the addition of the external additive means that the charge is controlled by components other than the external additive, and is hardly affected by the charging characteristics of the external additive. Generally, the toner is easily affected by an environmental change by an external additive. However, if the toner is not affected by the external additive, the toner is hardly affected by an environmental change. Therefore, there is an effect of not only stabilization of charging over time but also stabilization of charging against environmental changes.

In the present invention, the apparent specific gravity of the particles before the addition of the external additive is set to 0.35 or more,
The particles themselves have a certain degree of fluidity, and the amount of the external additive added can be reduced. Further, even if the amount of the external additive does not change, a decrease in fluidity due to burying of the external additive is suppressed.
The loose apparent specific gravity referred to in the present invention is a value measured with a powder tester manufactured by Hosokawa Micron.

As described above, in the case of particles in which the release agent is dispersed, the smaller the dispersion diameter, the higher the fluidity. However, in the case of a full-color toner, since a sufficient bleeding is required, a dispersion diameter of a certain degree or more is required, and the flowability tends to be poor. However, this problem is solved by setting the penetration of the release agent to 15 mm or less. That is, when the penetration of the release agent is 15 mm or less, the surface of the release agent becomes smooth, the fluidity of the particles becomes good, and the burying of the external additive is suppressed. The penetration of the release agent referred to in the present invention is a value measured based on JIS (K2235-80).

The binder resin in the present invention comprises a vinyl resin, a polyester resin or a polyol resin. Examples of the vinyl resin include homopolymers of styrene such as polystyrene, poly-P-chlorostyrene, and polyvinyltoluene and substituted products thereof: styrene-p-chlorostyrene copolymer, styrene-propylene copolymer, and styrene-vinyltoluene copolymer. Copolymer, styrene-vinylnaphthalene copolymer, styrene-methyl acrylate copolymer, styrene-ethyl acrylate copolymer, styrene-butyl acrylate copolymer, styrene-octyl acrylate copolymer, styrene-methacrylic acid Methyl copolymer, styrene-ethyl methacrylate copolymer, styrene-butyl methacrylate copolymer, styrene-α-chloromethyl methacrylate copolymer, styrene-acrylonitrile copolymer, styrene-vinyl methyl ether copolymer , Styrene-vinyl ethyl ether Copolymer, styrene-vinyl methyl ketone copolymer, styrene-butadiene copolymer, styrene-isoprene copolymer, styrene-acrylonitrile-indene copolymer, styrene-maleic acid copolymer, styrene-maleic acid ester copolymer Styrenic copolymers such as polymers: polymethyl methacrylate, polybutyl methacrylate, polyvinyl chloride, polyvinyl acetate and the like.

The polyester resin is composed of a dihydric alcohol as shown in the following group A and a dibasic acid salt as shown in the group B. May be added as the third component. Group A: ethylene glycol, triethylene glycol, 1,2-propylene glycol,
1,3-propylene glycol, 1,4-butanediol, neopentyl glycol, 1,4-butenediol, 1,4-bis (hydroxymethyl) cyclohexane, bisphenol A, hydrogenated bisphenol A, polyoxyethylenated bisphenol A , Polyoxypropylene (2,2) -2,2'-bis (4-hydroxyphenyl) propane, polyoxypropylene (3,3)-
2,2-bis (4-hydroxyphenyl) propane, polyoxyethylene (2,0) -2,2-bis (4-hydroxyphenyl) propane, polyoxypropylene (2,0) -2,2′-bis (4-hydroxyphenyl) propane and the like. Group B: maleic acid, fumaric acid, mesaconic acid, citraconic acid, itaconic acid, glutaconic acid, phthalic acid, isophthalic acid, terephthalic acid, cyclohexanedicarboxylic acid, succinic acid, adipic acid, sebacic acid, malonic acid, linoleic acid, or Esters of these acid anhydrides or lower alcohols. Group C: tri- or higher-valent alcohols such as glycerin, trimethylolpropane, and pentaerythritol; and tri- or higher-valent carboxylic acids such as trimellitic acid and pyromellitic acid. As the polyol resin, an epoxy resin and an alkylene oxide adduct of a dihydric phenol, or a compound having one active hydrogen in the molecule that reacts with the glycidyl ether and the epoxy group, and an active hydrogen that reacts with the epoxy resin in the molecule. There are compounds obtained by reacting two or more compounds. In addition, the following resins can be mixed and used as needed. Epoxy resin, polyamide resin,
Urethane resin, phenol resin, butyral resin, rosin, modified rosin, terpene resin, etc. A typical example of the epoxy resin is a polycondensate of a bisphenol such as bisphenol A or bisphenol F with epichlorohydrin.

The release agent in the present invention includes candelilla wax, carnauba wax, rice wax,
Examples include natural waxes such as jojoba wax, montan wax, paraffin wax, sasol wax, low molecular weight polyethylene, low molecular weight polypropylene, and alkyl phosphate. Among them, a hard resin that is incompatible with the binder resin, has little change in the charge amount due to the external additive, and is appropriately selected. The release agent is not limited to one kind,
More than one type of release agent may be mixed and used as a release agent that meets the conditions. The addition amount of the release agent is preferably 1 to 10%. If it is less than 1%, the effect as a release agent may not be exhibited, and if it is more than 10%, fluidity may be too bad.

As the colorant, dyes and pigments capable of obtaining toners of yellow, magenta, cyan, and black can be used. For example, carbon black, lamp black, ultramarine, aniline blue, phthalocyanine blue, phthalocyanine green, Hansa Yellow G,
Rhodamine 6G, lake, calco oil blue, chrome yellow, quinacridone, benzidine yellow, rose bengal, triallylmethane dye, etc.
Any conventionally known dyes and pigments can be used alone or in combination. The amount of these colorants used is usually 1 to 30%, preferably 2 to 20%, based on the binder resin.

In the present invention, a charge control agent may be added as required. When contained in a full-color toner, the charge control agent is preferably a transparent to white substance that does not impair the color tone of the color toner and that stabilizes and imparts the toner to a negative polarity or a positive polarity. Specifically, as the positive polarity, quaternary ammonium salts, imidazole metal complexes and salts are used,
As the negative polarity, metal salicylate complexes and salts, organic boron salts, calixarene-based compounds and the like are used.

In the case of inclusion in a black toner, a colored substance such as a metal complex of a nigrosine dye or a monoazo dye is used in addition to a charge control agent suitable for inclusion in a full-color toner.

The toner composition as described above can be prepared by any known toner mixing method and pulverizing method. The particle diameter of the toner is preferably about 3 to 10 μm in volume average particle diameter,
If the particle size is smaller than this, it may cause background contamination during development and may deteriorate the fluidity, impairing toner replenishment and cleaning performance. On the other hand, if it is larger than this, there may be problems such as dust during development and deterioration of resolution. Hydrophobic silica, titanium oxide, alumina, or the like is added to such colored particles as an external additive. If necessary, fatty acid metal salts (such as zinc stearate and aluminum stearate) and polyvinylidene fluoride may be added. The type and amount of these are determined so that the change in the amount of charge before and after the addition falls within the range described above.

[0027]

Hereinafter, the present invention will be described with reference to examples.
The present invention is not limited to this. The environmental change rate is a ratio of the difference between the charge amount in an environment of 30 ° C. and 80% (high temperature and humidity) and the charge amount in an environment of 10 ° C. and 15% (low temperature and humidity) to the charge amount of low temperature and humidity. It is.

The meanings of the symbols of the release agent and the external additive used in Examples and Comparative Examples are as shown in Tables 1 and 2.

[0029]

[Table 1]

[0030]

[Table 2]

Example 1 Binder resin: polyester resin 40 parts by weight Polyol resin 60 parts by weight Release agent: A (Table 1) 3 parts by weight Colorant: carbon black 10 parts by weight Part After thoroughly mixing the above materials with a blender,
The mixture was melt-kneaded with a twin-screw extruder heated to 0 ° C. The kneaded material was allowed to cool, coarsely pulverized by a cutter mill, pulverized by a fine pulverizer using a jet stream, and then colored with a parenteral classifier using an air classifier. The volume average particle diameter of the base colored particles measured by Coulter Counter Model TA-II (manufactured by Coulter Electronics Co., Ltd.) was 8.3 μm. The binder resin of the base colored particles contained 1.5% of a THF-insoluble component. Further, 0.4 part of the external additive b was mixed with 100 parts by weight of the base colored particles using a Henschel mixer to obtain a toner. Table 3 shows the charge amount of the release agent before and after the addition of the external additive, the charge amount of the toner before and after the addition of the external additive, the release agent dispersion diameter, and the apparent specific gravity of the looseness. The toner was mixed by a tumbler mixer at a ratio of 2.5 parts by weight to 100 parts by weight of a carrier obtained by coating a silicone resin on ferrite particles having an average particle diameter of 50 μm to obtain a developer. The obtained developer was set on a copier Imagio MF530 manufactured by Ricoh Co., Ltd. to produce an image. As a result, an image with high resolution was obtained without occurrence of offset. When a durability test (100,000 sheets) of this developer was performed, the charge amount per 10,000 sheets was in the range of +2 μc / g to −10 μc / g with respect to the initial value, and there was no problem. At this point, there was no toner scattering and no ground stains.

Example 2 Binder resin 40 parts by weight Polyester resin 60 parts by weight Mold release agent 3 parts by weight A (Table 1) Coloring agent 10 parts by weight carbon black Parts The same materials as in Example 1 with the addition of 1 part by weight of nigrosine dye were mixed well with a blender, and then 100 parts.
The mixture was melt-kneaded with a twin-screw extruder heated to １１０110 ° C.
The kneaded material was allowed to cool, coarsely pulverized by a cutter mill, pulverized by a fine pulverizer using a jet stream, and then used to obtain a mother colored particle using an air classifier. The volume average particle diameter of the base colored particles according to the Coulter Counter Model TA-II (manufactured by Coulter Electronics Co., Ltd.) was 8.2 μm. The binder resin of the base colored particles contained 1.4% of a THF-insoluble component. I was Furthermore, 0.4 parts of the external additive b and 0.2 parts of the external additive e were added to 100 parts by weight of the base colored particles,
The mixture was mixed with a Henschel mixer to obtain a toner. Table 3 shows the charge amount of the release agent before and after the addition of the external additive, the charge amount of the toner before and after the addition of the external additive, the release agent dispersion diameter, and the apparent specific gravity of the looseness.
The difference in charge amount between before and after the addition of the external additive to the toner due to the addition of the charge control agent was smaller than in the case of Example 1. Environmental fluctuations have also been reduced. The toner was mixed by a tumbler mixer at a ratio of 2.5 parts by weight to 100 parts by weight of a carrier obtained by coating a silicone resin on ferrite particles having an average particle diameter of 50 μm to obtain a developer. The obtained developer was set on a copying machine FT4820 manufactured by Ricoh Co., Ltd. to produce an image. As a result, an image with high resolution was obtained without occurrence of offset. When a durability test (100,000 sheets) of this developer was performed, the charge amount per 10,000 sheets was stable within a range of ± 5 μc / g with respect to the initial value. Further, even at the time of 100,000 sheets, toner scattering and background contamination did not occur.

Example 3 Binder resin: polyester resin 40 parts by weight Polyol resin 40 parts by weight Styrene-butyl acrylate copolymer resin 20 parts by weight Release agent: B (Table 1) 4 parts by weight Colorant .... Copper phthalocyanine blue pigment 2 parts by weight (CI Pigment B1uw15) After sufficiently mixing the above materials with a blender, 100 to 11
The mixture was melt-kneaded with a twin-screw extruder heated to 0 ° C. The kneaded material was allowed to cool, coarsely pulverized by a cutter mill, pulverized by a fine pulverizer using a jet stream, and then used to obtain a mother colored particle using an air classifier. The volume average particle diameter of the base colored particles measured by Coulter Counter Model TA-II (manufactured by Coulter Electronics Co., Ltd.) was 7.4 μm. There was no THF-insoluble component in the binder resin of the base colored particles. Further, 0.5 parts of the external additive b and 0.2 parts of the external additive d were mixed with 100 parts by weight of the base colored particles using a Henschel mixer to obtain a toner. Table 3 shows the charge amount of the release agent before and after the addition of the external additive, the charge amount of the toner before and after the addition of the external additive, the release agent dispersion diameter, and the apparent specific gravity of the looseness. This toner has a release agent dispersion diameter larger than that of Example 1 and a loose apparent specific gravity becomes smaller.
In order to improve the fluidity, it is necessary to add more external additive than in Example 1. However, by using two types of external additives, the difference in the charge amount of the release agent between before and after the addition of the external additive is obtained. Did not exceed 80%. Since the change in the charge amount of the release agent was small, the difference in the charge amount before and after the addition of the external additive to the toner did not increase.
The developer was mixed with a toner in a ratio of 5 parts by weight with respect to 100 parts by weight of a carrier obtained by surface-coating a silicone resin on ferrite particles having an average particle diameter of 50 μm to obtain a developer. The obtained developer was set on a pre-tail 550 of a copying machine manufactured by Ricoh Co., Ltd., and an image was displayed without setting oil in the fixing device. As a result, a clear color image having no offset was obtained. When a durability test (single color mode, 50,000 sheets) of this developer was performed, the charge amount per 10,000 sheets was -3 times the initial value.
It was stable in the range of μc / g to −8 μc / g. Since the dispersion diameter of the release agent is larger than that of Example 1, the amount of buried external additive is considered to be large, but the variation of the charge amount with time is small, and the toner scatters even at 50,000 sheets. There was no occurrence of background stain.

Example 4 Binder resin: polyester resin 100 parts by weight Release agent: C (Table 1) 6 parts by weight Coloring agent: copper phthalocyanine blue pigment 2 parts by weight (CI Pigment) Blue 15) Charge control agent: salicylic acid derivative zinc salt 0.4 part by weight Fluorine-containing quaternary ammonium salt 1.5 part by weight After sufficiently mixing the above materials with a blender, 100 to 11
The mixture was melt-kneaded with a twin-screw extruder heated to 0 ° C. The kneaded material was allowed to cool, coarsely pulverized by a cutter mill, pulverized by a fine pulverizer using a jet stream, and then used to obtain a mother colored particle using an air classifier. The volume average particle diameter of the base colored particles measured by Coulter Counter Model TA-II (manufactured by Coulter Electronics Co., Ltd.) was 7.8 μm. There was no THF-insoluble component in the binder resin of the base colored particles. Further, 1 part of the external additive c was mixed with 100 parts by weight of the base colored particles using a Henschel mixer to obtain a toner. Table 3 shows the charge amount of the release agent before and after the addition of the external additive, the charge amount of the toner before and after the addition of the external additive, the release agent dispersion diameter, and the apparent specific gravity of the looseness. Since the amount of the release agent added is larger than that of the conventional toner, the dispersion diameter of the release agent is large, and the toner is easily affected by the charging characteristics of the release agent. The difference in charge amount was also small. In addition, environmental fluctuation was small due to the effect of the charge control agent. The toner was mixed with a carrier in which ferrite particles having an average particle diameter of 50 μm and a silicone resin were surface-coated with 100 parts by weight of a carrier at a ratio of 5 parts by weight using a tumbler mixer to obtain a developer. The obtained developer was set on a pre-tail 550 of a copying machine manufactured by Ricoh Co., Ltd., and an image was displayed without setting oil in the fixing device. As a result, a clear color image free of offset was obtained. The durability test (single color mode,
(50,000 sheets). Although the amount of the release agent added was increased, the fluidity did not deteriorate over time, and even at the time of 50,000 sheets, there was no scattering of toner and no scorching of the background stain. Also, 1
The charge amount per 10,000 sheets is from +3 μc / g to the initial value.
The range was −12 μc / g, which was stable.

Example 5 Binder resin: 100 parts by weight of polyol resin Release agent: 5 parts by weight of D (Table 1) Colorant: 2 parts by weight of copper phthalocyanine blue pigment (C.I. Pigment Blue 15) Charge control agent: zinc salt of salicylic acid derivative 0.5 part by weight Fluorine-containing quaternary ammonium salt 1.0 part by weight After sufficiently mixing the above materials with a blender, 100 to 11
The mixture was melt-kneaded with a twin-screw extruder heated to 0 ° C. The kneaded material was allowed to cool, coarsely pulverized by a cutter mill, pulverized by a fine pulverizer using a jet stream, and then used to obtain a mother colored particle using an air classifier. The volume average particle diameter of the base colored particles measured by Coulter Counter Model TA-II (manufactured by Coulter Electronics Co., Ltd.) was 7.6 μm. There was no THF-insoluble component in the binder resin of the base colored particles. Further, 0.6 parts by weight of the external additive b and 0.6 parts by weight of the external additive c were mixed with 100 parts by weight of the base colored particles using a Henschel mixer to obtain a toner. The charge amount before and after the external additive is added to the release agent, the charge amount before and after the external additive is added to the toner, the release agent dispersion diameter,
Table 3 shows the loose apparent specific gravity. By using two types of external additives, the difference in charge amount between before and after the addition did not increase even if the addition amount was larger than in the case of one type. The developer was mixed with a toner in a ratio of 5 parts by weight with respect to 100 parts by weight of a carrier obtained by surface-coating a silicone resin on ferrite particles having an average particle diameter of 50 μm to obtain a developer.
The obtained developer was set on a pre-tail 550 of a copying machine manufactured by Ricoh Co., Ltd., and an image was displayed without setting oil in the fixing device. As a result, a clear color image having no offset was obtained. When a durability test (single color mode, 50,000 sheets) of this developer was performed, the charge amount per 10,000 sheets was +5 μc / g to −6 with respect to the initial value.
It was stable in the range of μc / g. Even at the time of 50,000 sheets, the fluidity was very good, and the toner was not scattered and the background was not stained.

Example 6 Binder resin: 100 parts by weight of polyester resin Release agent: 6 parts by weight of C (Table 1) Coloring agent: 2 parts by weight of copper phthalocyanine blue pigment (C.I. Pigment Blue 15) Charge control agent: salicylic acid derivative zinc salt 0.4 parts by weight Fluorine-containing quaternary ammonium salt 1.5 parts by weight The same materials as in Example 4 are sufficiently mixed with a blender, and then mixed with a blender. Heated to low 80-90 ° C 2
The mixture was melt-kneaded with an axial extruder. The kneaded material was allowed to cool, coarsely pulverized by a cutter mill, pulverized by a fine pulverizer using a jet stream, and then used to obtain a mother colored particle using an air classifier. The volume average particle diameter of the base colored particles measured by Coulter Counter Model TA-II (manufactured by Coulter Electronics Co., Ltd.) is 7.
It was 7 μm. T is contained in the binder resin of the base colored particles.
There were no HF insolubles. Further, the mother colored particles 100
0.8 parts by weight of the external additive c was mixed with a Henschel mixer to obtain a toner. Table 3 shows the charge amount of the release agent before and after the addition of the external additive, the charge amount of the toner before and after the addition of the external additive, the release agent dispersion diameter, and the apparent specific gravity of the looseness. The dispersion diameter of the release agent was smaller than in the case of Example 4, and the apparent specific gravity of the release agent was larger. As a result, even if the amount of the external additive was small, there was no difference in fluidity. Also, environmental fluctuations were small. The developer was mixed with a toner in a ratio of 5 parts by weight with respect to 100 parts by weight of a carrier obtained by surface-coating a silicone resin on ferrite particles having an average particle diameter of 50 μm to obtain a developer. The obtained developer was set on a pre-tail 550 of a copying machine manufactured by Ricoh Co., Ltd., and an image was displayed without setting oil in the fixing device. As a result, a clear color image having no offset was obtained. When a durability test (single color mode, 50,000 sheets) of this developer was performed, the charge amount per 10,000 sheets was stable in the range of +5 μc / g to −6 μc / g with respect to the initial value. Was.
Further, even at the time of 50,000 sheets, toner scattering and background stains did not occur.

Example 7 Binder resin: polyester resin 60 parts by weight Polyol resin 40 parts by weight Release agent: D (Table 1) 6 parts by weight Coloring agent: copper phthalocyanine blue pigment 2 parts by weight (CI Pigment Blue 15) Charge control agent: salicylic acid derivative zinc salt 0.4 parts by weight Fluorine-containing quaternary ammonium salt 1.5 parts by weight After sufficiently mixing the above materials with a blender, 100 to 11
The mixture was melt-kneaded with a twin-screw extruder heated to 0 ° C. The kneaded material was allowed to cool, coarsely pulverized by a cutter mill, pulverized by a fine pulverizer using a jet stream, and then used to obtain a mother colored particle using an air classifier. The volume average particle diameter of the base colored particles measured by Coulter Counter Model TA-II (manufactured by Coulter Electronics Co., Ltd.) was 7.4 μm. There was no THF-insoluble component in the binder resin of the base colored particles. Further, 0.2 parts by weight of the external additive a and 1 part by weight of the external additive d were mixed with 100 parts by weight of the base colored particles using a Henschel mixer to obtain a toner. The charge amount before and after the addition of the external additive of the release agent,
Table 3 shows the charge amount, the release agent dispersion diameter, and the apparent apparent specific gravity of the toner before and after the addition of the external additive. This toner was treated with an average particle size of 50
A developer was obtained by mixing at a ratio of 5 parts by weight with a Turbuler mixer to 100 parts by weight of a carrier obtained by coating a silicone resin on μm ferrite particles. The obtained developer is set in a Ricoh Copier Pretail 550,
An image was output without oil set in the fixing device. As a result, a clear color image having no offset was obtained. A durability test (single color mode, 50,000 sheets) of this developer was performed. The dispersion diameter of the release agent is larger than that of other toners, but since it is a hard release agent, it has the same dispersion diameter. The fluidity of the base particles was better than that of the toner of Example 4, and the buried amount of the external additive was smaller, and the fluidity of the developer over time was better than that of Example 4.
The charge amount per 10,000 sheets is ± 7 μc / g with respect to the initial value.
And toner scattering and background contamination did not occur even at 50,000 sheets.

Comparative Example 1 A toner was prepared in the same manner as in Example 1 except that the amount of the external additive used was changed to 1 part by weight. Table 3 shows the charge amount before and after the addition of the external additive of the release agent and the charge amount before and after the addition of the external additive to the toner. When this toner was used as a developer in the same manner as in Example 1, and an image was formed, a good image without occurrence of offset was obtained. However, this developer had a large change in the amount of charge with the passage of time, and at the time of 50,000 sheets, the toner value was 18 μc / g lower than the initial value, and toner scattering was severe. Further, the environmental change rate was worse than that of the first embodiment.

Comparative Example 2 The procedure of Example 4 was repeated, except that the charge control agent was omitted, the external additive c was replaced with the external additive d, and the amount used was changed to 0.8 part by weight. Colored base particles were prepared. .
Table 3 shows the charge amount of the release agent before and after the addition of the external additive, the charge amount of the toner before and after the addition of the external additive, the release agent dispersion diameter, and the apparent specific gravity of the looseness.
Shown in When this toner was used as a developer in the same manner as in Example 4, and an image was formed, a clear color image without occurrence of offset was obtained. However, in the durability test, the fluidity was poor, and at the time of 50,000 sheets, the toner value was reduced by 20 μc / g from the initial value, and toner scattering was severe. Environmental fluctuations were also large.

Comparative Example 3 Binder resin: 100 parts by weight of polyester resin Release agent: 6 parts by weight of D (Table 1) Colorant: 2 parts by weight of copper phthalocyanine blue pigment (C.I. Pigment Blue 15) Charge control agent: salicylic acid derivative zinc salt 0.2 part by weight Fluorine-containing quaternary ammonium salt 0.8 part by weight After sufficiently mixing the above materials with a blender, 100 to 11
The mixture was melt-kneaded with a twin-screw extruder heated to 0 ° C. The kneaded material was allowed to cool, coarsely pulverized by a cutter mill, pulverized by a fine pulverizer using a jet stream, and then used to obtain a mother colored particle using an air classifier. The volume average particle diameter of the base colored particles measured by Coulter Counter Model TA-II (manufactured by Coulter Electronics Co., Ltd.) was 7.7 μm. There was no THF-insoluble component in the binder resin of the base colored particles. Further, 1.0 part by weight of the external additive b and 0.8 part by weight of the external additive c were mixed with 100 parts by weight of the base colored particles using a Henschel mixer to obtain a toner. The charge amount before and after the external additive is added to the release agent, the charge amount before and after the external additive is added to the toner, the release agent dispersion diameter,
Table 3 shows the loose apparent specific gravity. The fluidity was poor due to the large dispersion diameter of the release agent, and a large amount of external additive was required.
The difference in charge amount between before and after addition did not increase by the combination of the kinds of external additives. The developer was mixed with a toner in a ratio of 5 parts by weight with respect to 100 parts by weight of a carrier obtained by surface-coating a silicone resin on ferrite particles having an average particle diameter of 50 μm to obtain a developer. The obtained developer was set on a pre-tail 550 of a copying machine manufactured by Ricoh Co., Ltd., and an image was displayed without setting oil in the fixing device. As a result, a clear color image having no offset was obtained. A durability test (single color mode) of this developer was performed. Since the release agent had a large dispersion diameter and was not very hard, the fluidity was poor at 10,000 sheets with time, and the toner was scattered. Was intense.

[0041]

[Table 3]

[0042]

As described above, the toner of the present invention has a long-term stable coloring characteristic without being affected by environmental changes.

Claims (7)

[Claims] At least a binder resin, a colorant, and a binder resin are made of an incompatible release agent, and the dispersion diameter of the release agent is 0.2 μm.
m, and having inorganic fine particles adhered to the particle surface, wherein the toner has a charge amount of −10 μc / g to −50.
μc / g, or 10 μc / g to 50 μc / g, and the difference between the charge amount of the particles before the addition of the inorganic fine particles and the charge amount of the toner after the addition of the inorganic fine particles is 50 to the charge amount of the toner. % For electrophotography. 2. A toner comprising at least a binder resin, a colorant, and a release agent incompatible with a binder resin and having inorganic fine particles adhered to the particle surface, wherein the binder resin is present in the toner. Has no THF-insoluble component and the dispersion diameter of the release agent is 0.2 to 1
μm, the toner charge amount is −10 μc / g to −50 μc
/ G, or 10 μc / g to 50 μc / g, and the difference between the charge amount of the particles before the adhesion of the inorganic fine particles and the charge amount of the toner after the adhesion of the inorganic fine particles is 30% with respect to the charge amount of the toner. Full color toner for electrophotography characterized by not exceeding. 3. The electrophotographic toner according to claim 1, wherein the external additive is a combination of two or more kinds. 4. The method according to claim 1, wherein the difference between the charge amount of the release agent before adding the inorganic fine particles and the charge amount after adding the inorganic fine particles does not exceed 80% with respect to the charge amount after adding the inorganic fine particles. Item 4. The electrophotographic toner according to item 2 or 3. 5. The electrophotographic toner according to claim 1, further comprising a charge control agent. 6. The loose specific gravity of the particles before the attachment of the inorganic fine particles is 0.35 or more.
6. An electrophotographic toner according to any one of claims 1 to 5. 7. The electrophotographic toner according to claim 2, wherein the penetration of the release agent is 15 or less.